There are a few birthdays this week, not least the 40th anniversary of what was once the Newcastle Playhouse, and is now Northern Stage. The building was transformed four years ago and, under the leadership of Erica Whyman, it continues to be one of the UK's most interesting and innovative regional theatre companies. As part of the celebrations, Northern Stage has begun a project called 40 Babies, working with 40 newborns and their families to create what it calls a "living book" of their first year. It then has the ambition of creating work with, and for, 0-3 year-olds.